/// <summary>
/// 得到短参数信息
/// </summary>
/// <param name="param">参数</param>
/// <param name="key">md5盐（默认）</param>
/// <param name="number">生成短连接的长度</param>
/// <returns>得到短参数的值（有四个，任选其一即可）</returns>
public static string[] GetShortParam(string param, string key = null, int number = 6)
{
string hex = SecurityCommon.GetMd5Hash(key + param);
string[] resUrl = new string[4];
for (int i = 0; i < 4; i++)
{
int hexint =
0x3FFFFFFF & Convert.ToInt32("0x" + hex.Substring(i * 8, 8), 16); //把加密字符按照8位一组16进制与0x3FFFFFFF进行位与运算
string outChars = string.Empty;
for (int j = 0; j < number; j++)
{
//把得到的值与0x0000003D进行位与运算，取得字符数组chars索引
int index = 0x0000003D & hexint;
//把取得的字符相加
outChars += _chars[index];
//每次循环按位右移5位
hexint = hexint >> 5;
}
resUrl[i] = outChars; //把字符串存入对应索引的输出数组
}
return(resUrl);
}
/// <summary>
/// 得到sha系列加密信息
/// </summary>
/// <param name="stream">文件流</param>
/// <param name="hashAlgorithm">加密方式</param>
/// <param name="isUpper">是否大写</param>
/// <returns></returns>
public static string GetSha(Stream stream, HashAlgorithm hashAlgorithm, bool isUpper = true)
{
if (stream == null)
{
throw new BusinessException("FileStream is Null", HttpStatus.Err.Id);
}
byte[] retval = hashAlgorithm.ComputeHash(stream);
stream.Close();
return(SecurityCommon.GetSha(retval, hashAlgorithm, isUpper));
}